Self-propelled machine and method for laying a catenary and/or a contact wire of an overhead line

ABSTRACT

A self-propelled machine for continuously laying an overhead line extending above a track and attached to pylons spaced alongside the track, which comprises machine frame movable along the track in an operating direction, a power-driven, vertically and laterally adjustable work platform mounted on the machine frame for an operator assigned to attaching the overhead line to the pylons, a storage drum mounted on the machine frame, a length of the catenary and/or the contact wire of the overhead line being reeled on the storage drum and the drum being rotatable at a pay-out speed for unreeling the catenary and/or the contact wire, and a drive control for adjusting the moving speed of the machine frame in response to the pay-out speed of the catenary and/or the contact wire. A lifting device is mounted on the machine frame and includes a power-driven, vertically adjustable and laterally pivotal boom, and a support and guide pulley carried by the boom and arranged to support and guide the unreeled catenary and/or contact wire from the storage drum to the operator on the work platform at a constant height determined by the vertical adjustment of the boom and a lateral position determined by the pivoting of the boom, and a device is mounted on the machine frame between the storage drum and the pulley for continuously guiding and tensioning the catenary and/or contact wire, the guiding and tensioning device including a power-driven guide roller guiding the tensioned catenary and/or contact wire to the support and guide pulley, and a drive control for the guide roller.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a self-propelled machine for laying acatenary and/or a contact wire of an overhead line extending above atrack and attached to pylons spaced alongside the track, which comprisesa machine frame having two opposite ends, undercarriages supporting themachine frame at the ends thereof for mobility on the track, a drive formoving the machine frame along the track in an operating direction, adriving operator's cab mounted on the machine frame, a power-driven,vertically adjustable work platform mounted on the machine frame for anoperator assigned to attaching the overhead line to the pylons, astorage drum mounted on the machine frame, a length of the catenaryand/or contact wire being reeled on the storage drum and the drum beingrotatable at a pay-out speed for unreeling the catenary and/or contactwire, a drive control for adjusting the moving speed of the machineframe in response to the pay-out speed of the catenary and/or contactwire, a lifting device mounted on the machine frame, the lifting deviceincluding a power-driven, vertically adjustable and laterally pivotalboom and a support and guide pulley carried by the boom and arranged tosupport and guide the unreeled catenary and/or contact wire from thestorage drum to the operator on the work platform, and a controllabledevice for tensioning the catenary and/or contact wire, which includes aguide roller.

(2) Description of the Prior Art

German patent No. 2,211,247, published Feb. 19, 1981, cites pages 214 to226 of "Fahrleitungsnetz" by I. I. Wlassow, published in 1955 byFachbuchverlag Leipzig, as state of the art. This publication discloseslaying an overhead line comprised of a catenary and contact wire above atrack by first affixing one end of the catenary and then guiding it overrollers mounted at spaced locations. For this purpose, use is made of amobile car running on the track and carrying a rotatable storage drumfor the catenary, and a brake is provided for the drum. After a sectionof the catenary has been laid, the catenary is tensioned or stretched bya tackle and the free end of the stretched catenary is permanently fixedin position. Subsequently, hangers are attached to the catenary and thecontact wire is laid in the same manner and is suspended from thecatenary by temporary hangers. The contact wire is then tensioned orstretched by one or more tackles and is fixed, whereupon it is attachedto the permanent hangers. Laying an overhead line in this mannerrequires considerable work. Paying out or reeling the catenary and thecontact wire on the storage drums is relatively difficult because theydo not extend parallel to the track but in a zig-zag formation from oneside of the track to the opposite side where the overhead line isaffixed to spaced pylons at the track shoulders. It is, therefore, verytime-consuming to obtain a proper pay-out of the catenary and thecontact wire from the drum to its final position.

"Japanese Railway Engineering", Vol. 9, 1968, pages 23-25, discloses acatenary inspection and catenary stretching car for the inspection andsimple repair of an overhead line. The car carries rotatable storagedrums for the contact wire. When the contact wire is extended, the drumis braked by an oil pressure brake so that the contact wire ma be laidwhile tensioned. The car is not used for laying a new overhead linecomprised of a catenary and a contact wire but only to replace a worncontact wire by a new contact wire on a catenary and hangers which arealready in place. A rapid and accurate laying of the contact wire and/orthe catenary is not possible with this car because of their zig-zagextension which is not parallel to the track.

German patent No. 526,889, published June 11, 1931, discloses a mobilecar running on a track for laying an electrical overhead line above thetrack. Several wire storage drums are mounted on the car which alsocarries a lifting arm for raising the wires reeled off the drums to thelevel of hooks above the track, to which the wires are attached. Thisarrangement makes it possible to lay several wires simultaneously butthese wires are not connected to each other. An accurate pay-out of thewires from the drum encounters the above-described difficulties becausethey wires do not extend parallel to the track.

The above-cited German patent No. 2,211,247 discloses a machine of thefirst-described type for the temporary installation of an overhead line.The self-propelled car of this machine carries the following structures:drums for storing the catenary cable and the contact wire and for payingthem out under a controlled tension; a hook-sensing device; a tensioningdevice control with a drive for imparting a longitudinally extendingtensioning force; a device for delivering the wire hangers; a suspensiondevice operating in response to a sensing signal for suspending thecatenary in the hooks; and an anchoring device for the other end of thecatenary and/or the contact wire. A lifting arm, which is verticallyadjustable by a power drive, is mounted between the drums and an upperportion of the contact wire and catenary and a carrier arm for tworelatively small-diameter guide pulleys spaced from each other in thelongitudinal extension of the machine frame lift and support the contactwire and the catenary, and a similarly small-diameter guide rollerguides them over the tensioning device to the drums. This machineconstruction is of a relatively complex design and still is useful onlyfor the temporary or provisional installation of the contact wire andcatenary under tension. It, too, makes an accurate pay-out of thecontact wire and the catenary from the drums as well as guidance overthe tensioning device and guide rollers difficult, if not impossible,because in its final and permanent position, they extend in a zig-zagformation. Furthermore, the distance between the lifting device and thestorage drums is relatively large in the longitudinal extension of themachine frame, which requires long connection wires for affixing theends of the contact wire and/or catenary to the pylons. In particular,the machine requires an expensive and complex hook-sensing device aswell as a device for delivering temporary hangers in connection with thewire-suspension device to make it possible at least approximately toguide the vertically and laterally adjustable carrier arm equipped withguide pulleys on the vertically adjustable work platform so that it canfollow the alternating change in direction of the catenary and/orcontact wire as it extends from pylon to pylon on the opposite trackshoulders--and even this only provisionally. The suspension of thetensioned catenary is effected by the two spaced guide pulleys which arelifted with the carrier arm and the catenary section extending betweenthe pulleys is suspended on the temporary hook therebetween. Thisprovisional installation is very uneconomical and time-consuming, andthe temporary hangers must be removed after the provisional installationin a subsequent operation to enable the permanent attachment elements tobe mounted during a subsequent tensioning and orienting operation.

SUMMARY OF THE INVENTION

It is the primary object of this invention to provide an overhead lineinstallation machine of the first-described type which is simple instructure and operation, and which enables the laying of the catenarycable and/or the contact wire of the overhead line to be effectuatedmore simply and under high tension thereof.

The above and other objects are accomplished according to one aspect ofthe invention with a self-propelled machine for continuously laying atleast one of two elongated flexible elements of an overhead lineextending above a track and attached to pylons spaced alongside thetrack, one of the two elongated flexible elements being a catenary cableand the other elongated flexible element being a contact wire, whichcomprises a machine frame having two opposite ends, undercarriagessupporting the machine frame at the ends thereof for mobility on thetrack, a drive for moving the machine frame along the track in anoperating direction, and a driving operator's cab mounted on the machineframe. A power-driven, vertically and laterally adjustable work platformfor an operator assigned to attaching the overhead line to the pylonsand a storage drum are mounted on the machine frame, a length of theelongated flexible element being reeled on the storage drum and the drumbeing rotatable at a pay-out speed for unreeling the elongated flexibleelement. The machine further comprises a drive control for adjusting themoving speed of the machine frame in response to the pay-out speed ofthe elongated flexible element, a lifting device mounted on the machineframe, the lifting device including a power-driven, verticallyadjustable and laterally pivotal boom and a support and guide pulleycarried by the boom and arranged to support and guide the unreeledelongated flexible element from the storage drum to the operator on thework platform at a constant height determined by the vertical adjustmentof the boom and a lateral position determined by the pivoting of theboom, and a device mounted on the machine frame between the storage drumand the pulley for continuously guiding and tensioning the elongatedflexible element, the guiding and tensioning device including apower-driven guide roller guiding the tensioned elongated flexibleelement to the support and guide pulley, and a drive control for theguide roller.

A machine of this structure is simple to build and operate, and it makesit possible to lay or replace overhead line catenaries and/or contactwires simply, accurately and rapidly in a desired position. It is notnecessary for the operating personnel to effectuate difficult andtime-consuming centering, retaining and adjusting steps with respect tothe catenary and/or contact wire because they are laid on the fasteningelements at the pylons in their desired, tensioned position, in whichthey are then fixed to the pylons.

More particularly, the machine of the invention makes it possible forthe first time to fasten the catenary and the contact wire permanentlyto the steady braces on the pylons and to attach the hangers to thecatenary and contact wire in a single operating stage as the catenaryand contact wire are simultaneously reeled off their storage drums Thus,the machine produces a finished, stretched and installed overhead linewithout requiring any subsequent operations and the use of additionalmachines The construction of the support and guide pulleys and of thetensioning device with its guide roller assures a continuous support andstretching of the catenary and/or the contact wire so that they will becontinuously maintained under their required tension as they are reeledoff the storage drums The continuous support of the catenary and/orcontact wire at their desired elevations enables them to be centeredalong their zig-zag path from side-to-side of the track simply andwithout problems, and without requiring complicated and time-consumingoperations, by simply laterally pivoting the support and guide pulleyswhile maintaining the adjusted height unchanged at the desiredelevation. For all these reasons, the machine is very economical and maybe used in the same advantageous manner for detaching an overhead lineto be replaced

According to another aspect of the invention, there is provided anapparatus for continuously reconstructing such an overhead line, whichcomprises two like self-propelled machines of the above-described typefor respectively continuously laying and receiving the overhead line,and a work car coupled to each self-propelled machine, each work carcomprising a power-driven, vertically adjustable and longitudinallydisplaceable work platform.

Such an apparatus makes it possible completely to dismount an oldoverhead line and to install a new overhead line with relatively littlepersonnel in a single operation. The vertically adjustable andlongitudinally displaceable work platforms on the work cars allow theoperators sufficient time for the dismounting and affixing work whilethe machines continuously advance along the track, and other necessaryreconstruction work is done.

According to yet another aspect, the invention provides a method forcontinuously laying an overhead line, which comprises the steps ofpropelling a machine carrying respective storage drums for the catenarycable and the contact wire along the track, unreeling the catenary cableand the contact wire from respective storage drums while the machine ispropelled along the track, subjecting the unreeled catenary cable andcontact wire to a controlled tension force while they are wound about aguiding and tensioning device mounted on the machine, supporting andguiding the unreeled, tensioned catenary cable and contact wire byrespective support and guide pulleys vertically and laterally adjustablymounted on the machine, vertically and laterally adjusting the pulleysto maintain the tensioned catenary cable and contact wire at acorresponding vertical and lateral position adjacent a respective one ofthe pylons at one side of the track, attaching the overhead line to therespective pylon whereby the catenary cable and the contact wire arefixed in said position, subsequently laterally adjusting the support andguide pulleys to position them adjacent a succeeding one of the pylonsat the opposite side of the track while maintaining the supporting andguide pulleys at a constant vertical adjustment and propelling themachine along the track whereby the overhead line assumes a zig-zag pathbetween succeeding pylons and the catenary cable and contact wire arecentered along said path, and affixing hangers between the catenarycable and the contact wire of the attached overhead line in a trailingoperation immediately following the attachment operation to maintain thecatenary cable and the contact wire at the desired vertical position

This succession of steps for the first time makes it possible in asingle simple and economical operation to lay an overhead line and fixit in its desired position Beginning with the unreeling of the catenaryand the contact wire to the final affixing thereof to the steady bracesand to the hangers, respectively, the operation proceeds withoutinterruption in the manner of a moving assembly line, the operationalsteps being coordinated in a highly efficiently manner. Since thecatenary and the contact wire are unreeled under their respectiverequired tensions, which often differ considerably from each other, attheir respective desired levels, a simple, rapid and final affixing ofthe overhead line components is possible.

DETAILED DESCRIPTION OF THE DRAWING

The above objects, advantages and features of the present invention willbecome more apparent from the following detailed description of certainnow preferred embodiments thereof, taken in conjunction with theaccompanying, generally schematic drawing wherein

FIG. 1 is a side elevational view of a machine for installing ordismounting the catenary and/or the contact wire of an overhead line inan installing position immediately following a pylon, which comprises aboom car followed by a tower car;

FIG. 2 is a top view of the machine but, for a better understanding, thestorage drums for the catenary and contact wire are shown in anintermediate position and the support and guide pulleys illustrated inFIG. 5 are not shown;

FIG. 3 is an enlarged perspective top view of one of two tensioningdevices in its laying position, the tensioning device being constitutedby a winch, and of the two support and guide pulleys supported on alifting device;

FIG. 4 is an enlarged end view of the machine, as seen in the directionof arrows IV--IV of FIG. 2;

FIG. 5 is an enlarged top view of the two support and guide pulleys inthe intermediate position shown in FIG. 2;

FIG. 6 shows an embodiment of support and guide pulleys supported on alifting device for guiding the catenary and the contact wire to thedesired level;

FIG. 7 diagrammatically illustrates another embodiment of support andguide pulleys adjustable in relation to each other by a power drive andsupported on a lifting device constituted by a pivotal crane; and

FIG. 8 is a diagrammatic side view of two machines constructed accordingto the invention and operated in tandem for dismounting an old overheadline and installing a new overhead line.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 show self-propelled machine 1 for continuously laying orreceiving at least one of two elongated flexible elements of overheadline 4 extending above track 7 and attached to pylons 52 spacedalongside the track, one of the two elongated flexible elements beingcatenary cable 3 and the other elongated flexible element being contactwire 2. The track is comprised of rails 6 fastened to ties 5. Themachine comprises machine frame 10 having two opposite ends andundercarriages 8 support the machine frame at the ends thereof formobility on the track. Drive 9 moves machine frame 10 along track 7 inan operating direction indicated by arrow 14, and driving operator's cab11 is mounted on the machine frame. Drive 9 has sufficient power to pullabout 10 to 12 tons and can move the machine frame up an incline of upto 30 pro mil. If only a single machine moving drive 9 is provided, asillustrated at the left in FIG. 1, it is connected by the dash-dot linesto the other drives, particularly the drives for the tensioning winches.Power-driven, vertically and laterally adjustable work platform 13 ismounted on the machine frame for an operator assigned to attaching theoverhead line to pylons, hydraulic drives 12 enabling the work platformto be adjusted to the desired height and lateral position. Respectivestorage drum 33, 34 is mounted on machine frame 10 and a length of theelongated flexible element 3, 2 is reeled on the respective storage drumwhich is rotatable at a pay-out speed for unreeling the elongatedflexible element. Drive 9 is controlled for adjusting the moving speedof the machine frame in response to the pay-out speed of the elongatedflexible element. Lifting device 20 is also mounted on machine frame 10and includes power-driven, vertically adjustable and laterally pivotalboom 17, and a respective support and guide pulley 18, 19 carried byboom 17 and arranged to support and guide the unreeled elongatedflexible element 3, 2, respectively, from respective storage drum 34, 33to the operator on work platform 13 at a constant height determined bythe vertical adjustment of boom 17 and a lateral position determined bythe pivoting of the boom. Illustrated lifting device 20 is a pivotalcrane 22, boom 17 being a telescopingly arranged arm extending in thedirection of the longitudinal extension of machine frame 10, and furthercomprises power drive 15 linking the boom to the crane for verticallyadjusting the boom, power drive 16 for laterally adjusting the crane andpower drive 21 for telescopingly adjusting the boom arm to an extensionof about 10 m, the crane being mounted on machine frame 10 ahead ofstorage drums 34, 33 in the operating direction. The power drives enablesupport and guide pulleys 18, 19 on boom 17 to be adjustably positionedabove a space centered between the two storage drums. This simple cranearrangement enables the support and guide pulleys to be placed rapidlyand without problems into their most favorable operating positions alongthe machine frame and permits them to be swung back and forth laterallyto obtain the desired zig-zag path of the overhead line, thecantilevered construction of the pivotal crane dependably excluding anypossible interference with the unreeling of the catenary and the contactwire from their storage drums.

The illustrated machine further comprises respective device 37, 38mounted on machine frame 10 between respective storage drum 33, 34 andrespective pulley 19, 18 for continuously guiding and tensioning contactwire 2 and catenary 4, respectively, each guiding and tensioning deviceincluding, respectively, power-driven guide roller 41 guiding thetensioned contact wire and catenary, respectively to support and guidepulleys 19, 18, and drive control 45 for each guide roller.

Support and guide pulleys 18, 19 and guide rollers 41 are arranged forguiding the catenary and the contact wire along a path extendingsubstantially perpendicularly to rotary axes 25, 26 of the pulleys andof the rollers independently of the lateral position of boom 17. Thesupport and guide pulleys are also power-driven and they are supportedon carrier member 28 rotatably for pivoting about vertical axis 27whereby the catenary and contact wire are automatically centered andoriented in a longitudinal direction when the overhead line extends in alateral zig-zag path between successive pylons 52 at respective sides ofthe track. The support and guide pulleys are universally pivotal bymounting them on respective holders 31 on an outer end of carrier member28 remote from vertical pivoting axis 27, each holder being rotatableabout respective axis 29, 30 extending perpendicularly to vertical axis27 substantially parallel to the longitudinal direction. The pivotalcarrier member for the support and guide pulleys provides an automaticcentering means for the catenary and contact wire while providing asolid connection to boom 17, which can withstand very high tensileforce. The pivoting of the carrier member will automatically adjust thepulleys along the zig-zag path of the overhead line while the verticallyadjusted boom will hold them at the desired level. The universalpivoting arrangement will continuously hold the catenary and contactwire in the circumferential grooves of the pulleys, regardless of thelateral position of the boom, so that they will securely be retained inthe pulley grooves during the entire operation.

The vertical and lateral adjustment by power drives 15 and 16 enablessupport and guide pulleys 18, 19 to be brought into their desiredvertical and lateral position where they hold the catenary and contactwire, the pivoting of carrier member 28 about vertical axis 27dependably centering the overhead line along the zig-zag path.

Each guide roller 41 is positioned below the associated support andguide pulley 18, 19 and is mounted on machine frame 10 for tilting aboutaxis 39 extending in the longitudinal extension of machine frame 10 andperpendicularly to the rotary axis of the roller. This relativepositioning of the guide rollers and their associated pulleys provides aparticularly compact arrangement enabling the machine frame to berelatively short while the tilting of the rollers enables the unreelingcatenary and contact wire to adapt their paths to the lateral positionof the support and guide pulleys.

The storage drums are capable of carrying about 900 to 1600 meters ofcatenary cable and contact wire, respectively, reeled on the drums,having an approximate weight of two to three tons and a cross sectionalarea of about 70 and 110 mm², respectively. The support and guidepulleys as well as the guide rollers have circumferential groovesaccommodating the catenary and contact wire, and each pulley andassociated roller are so positioned relative to each other that thecatenary and contact wire will be deflected by at least 90° as it isguided from the roller to the pulley. The contact wire is relativelystiff, and pulley 19 and roller 41 have substantially the same diameterwhich is preferably at least about one meter, depending on the wiregauge. This arrangement and coordination of the support and guide pulleywith the guide roller of the tensioning device provides an accurate andsecure guide of the catenary and the contact wire without subjecting thesame to undue flexing forces so that such relatively stiff flexibleelongated elements will be unreeled, tensioned and deflected withoutproblems.

Each device 37, 38 for continuously guiding and tensioning elongatedflexible element 2, 3 further comprises another guide roller 64, 65,respectively connected with power-driven guide roller 41 for rotation intandem therewith by means of chain drive 40. The guide rollers arerotatable by power drives 45 about transverse axes 65 extending parallelto each other and are tiltable about axis 39 which extendsperpendicularly to the rotary axes of the rollers Drives 45 are eachconnected to central hydraulic fluid pump 46 supplying power to thedrives. The tandem guide rollers form winches 35, 36 about which therespective elongated flexible element may be wound several times forobtaining a desired and measurable tensioning rotary moment. The guiderollers of each winch have the same diameter but the roller diameters ofwinch 35 for tensioning contact wire 2 are smaller than those of winch36 for tensioning the catenary. Respective tension monitoring device 59,60 is arranged between winch 35, 36 and support and guide pulley 19, 18in contact with contact wire 2 and catenary 3, respectively, formeasurably determining and maintaining a selected constant tensionthereof, and the tension monitoring devices are connected to centralcontrol 50 and to drive controls 45 for the guide rollers of the winchesas well as machine drive 9. The tension monitoring devices preferablyhave odometers incorporated therein. The preferred tension of thecontact wire and of the catenary is about 1000 and 700 kg, respectively.The arrangement of the tension monitoring devices enables asubstantially constant tension of the contact wire and the catenary tobe maintained independently of the forward speed of machine 1 so thatthe unreeled contact wire and catenary supported and guided by pulleys19 and 18 may be immediately fastened to the pylons. Since the tensionmonitoring devices are mounted between winches 35, 36 and pulleys 19,18, the pulleys may be laterally adjusted along the zig-zag path of theoverhead line without interfering with these devices. Winches arestructurally relatively simple and robust guiding and tensioning devicesfor braking the unreeled elongated flexible elements forcefully toimpart a uniform and high tension thereto. Since the tandem guiderollers tilt about axis 39, the flexible elongated element will be woundabout the winch without any problems, regardless of its tilted position.

In the illustrated embodiment, a respective common cradle 23, 24supports each storage drum 34, 33 and the tensioning winch 38, 37, thecradles being mounted on machine frame 10 for tilting or rocking aboutaxis 39. As shown in FIG. 3, each storage drum is mounted on bearing 70of its cradle for rotation about rotary axis 69. Power drive 66 rotatesthe storage drum which is arranged on bearing 70 for transversedisplacement parallel to rotary axes 65 of guide rollers 64, 65, 41 bypower drive 67. In this manner, the storage drums and tensioning winchesare titled in unison and tilting of the cradles changes the inclinationof the drums and the axes of the guide rollers to adapt the paths of thecatenary and contact wire to the changing lateral positions of supportand guide pulleys 18, 19. The transverse displacement of the storagedrums in combination with their tilting assures an accurate unreeling.It assures that the elongated flexible element coming from thetensioning winch will always arrive at the storage drum at the samepoint and perpendicularly to the rotary axis of the support and guidepulley, which produces a uniform and troublefree operation of the winch.Rotary drive 66 assures a troublefree reeling of the elongated flexibleelement when the machine is used for dismounting an overhead line.

Work platform 13 has been shown in full lines in FIGS. 1 and 2 in itsposition during transit of machine 1 while one operating positionthereof has been shown in phantom lines in FIG. 1 and two of manypossible lateral operating positions have been indicated in phantomlines in FIG. 2. Rotary axes 25, 26 of support and guide pulleys 18, 19,rotary axes 65 of the guide rollers of winches 35, 36 and rotary axes 69of storage drums 33, 34 have been shown in their horizontal (center)positions, for the sake of simplicity of illustration. The rotary axesare in this horizontal position when pulleys 18, 19 are exactly abovethe center line of the track as they move laterally from side to sidewhen they lay the overhead line in its zig-zag path, or during transitwhen the machine is not in operation. When the contact wire and catenarysupport and guide pulleys are laterally moved according to the requiredzig-zag path of overhead line 4, with a maximum distance of about 40 cmfrom the track center line, the rotary axes will be somewhat inclined tothe horizontal, as will be explained in more detail hereinafter inconnection with FIGS. 3 and 4. FIG. 1 also shows the storage drums,guide rollers and support and guide pulleys in their vertical positionsalthough they will be slightly inclined (see FIG. 3) when they arelaterally spaced from the track center line during the installation ordismounting of the overhead line.

While the machine could be used with a single storage drum andassociated tensioning device and support and guide pulley for layingand/or receiving only the catenary or the contact wire of an overheadline, the hereinabove described and illustrated arrangement has theadvantage of enabling the catenary and the contact wire to be installedor dismounted at the same time without interference with each other.Thus, the machine can be used for simultaneously unreeling the contactwire and the catenary, and in the same operating stage to fix them tothe pylons, providing a very productive and economical operation for theinstallation as well as the dismounting of an entire overhead line or ofone of its flexible elongated elements. Pulleys 18, 19 will support andguide the catenary cable and the contact wire from respective storagedrums 34, 33 to the operator on work platform 13 at respective constantheights a of catenary 3 and b of contact wire 2, these heights beingrespectively determined by the vertical adjustment of boom 17 and thevertical distance of pulleys 18, 19 from each other as well as thelateral position determined by pivoting the boom by power drive 16.

It is advantageous to mount support and guide pulleys 18, 19 forrelative vertical adjustment in relation to each other so that distancec between contact wire 2 and catenary 3 may be adjusted, and in thepreferred embodiment illustrated herein, power drive 32 links holder 31of pulley 19 by means of a linkage system to carrier member 28. Asshown, contact wire support and guide pulley 19 trails catenary cablesupport and guide pulley 18 in the operating direction, which enablesthe laying of the contact wire and the catenary to proceed withoutinterference with each other and the level of the contact wire may bechanged by operation of drive 32 without interference by precedingpulley 19 for the catenary.

As best shown in FIG. 2, reserve storage drums 42 and 43 for thecatenary cable and for the contact wire, respectively, are mounted onmachine frame 10 between cradles 23 and 24. They can be transported onhook 44 on boom 17 of pivotal crane 20.

In the preferred embodiment illustrated herein, driving operator's cab11 is mounted on machine frame 10 at leading end 62 of the machine framein the operating direction, lifting device 20 is mounted on the machineframe immediately behind cab 11 in the operating direction and workplatform 13 is mounted on the machine frame at the opposite, trailingmachine frame end 63, which has material storage space 48 adjacent thework platform. The work platform carries fenced-in operator's station 47which houses central control 50 including digital indicator instrument49 for indicating the tension of the unreeled elongated flexible element2, 3. Central control 50 is connected to power drives 9, 15, 16 and 45for respective remote control of the machine moving speed, the verticaland lateral adjustment of lifting device 20 and the rotation of theguide rollers of winches 37, 38. The lifting device comprises verticalmeasuring and indicating instrument 61. Arranging the lifting device andthe work platform at opposite ends of the machine frame enables anoperator on the platform to observe the positioning of support and guidepulleys 18, 19 without interference, and monitoring the verticaladjustment of lifting device 20 makes it possible to adjust the level ofthe pulleys accurately at all times by remote control. The centralcontrol of the power drives enables the operator at station 47, who hasan excellent view of the entire operation, to control the zig-zag pathof the overhead line according to the prevailing conditions. Digitaltension indicator 49 enables the operator to change the tensionimmediately if a deviation from the desired tension is registered.

FIGS. 1 and 2 show respective operating positions of operator's station47 in phantom lines, operator 51 at the station operating centralcontrol 50 and attending to the attachment of catenary 3 and contactwire 2 to steady brace 53 affixed to pylon 52. In the illustratedembodiment, machine 1 is combined with a trailing, self-propelled towercar 55 equipped with drive 54 and carrying vertically adjustable worktower 56 for an operator assigned to detach and attach hangers 57connecting contact wire 2 to catenary 3 and steady braces 53 attachingthe overhead line to the pylons. Vertically and laterally adjustablecrane 58 is mounted on a leading machine frame end of the tower car fortransporting the parts, i.e. hangers 57, to the work tower. Thiscombination has the advantage that the final mounting of the overheadline may be effected in the same operating stage with the laying of thetensioned catenary and contact wire in their desired positions.

Referring now to FIG. 3, support and guide pulleys 18, 19 are shown intheir lateral positions, with their rotary axes 25, 26 slightly inclinedwith respect to the horizontal, these pulley positions being produced bylaterally pivoting crane 22. Rotary axes 65 of the guide rollers oftensioning winch 36 (and of winch 35 not shown in this figure) as wellas rotary axis 69 of storage drum 34 for the catenary (and of contactwire drum 33 not shown) are similarly inclined. Each pulley hascircumferential groove 72 holding the respective elongated flexibleelement 2. Guide rollers 41, 64 of winch 36 are mounted on bearings 73for rotation about axes 65. Cradle 23 comprises first frame part 74defining opening 76 accommodating storage drum 34 and adjoining framepart 75 whereon guiding and tensioning device 36 is mounted. Cradle 24mounting storage drum 33 and winch 35 is similarly constructed but issomewhat larger and stronger, the two cradles being mounted on machineframe 10 in succession in the longitudinal extension thereof, as shownin FIGS. 1 and 2. Opening 76 is wide enough to permit the transversedisplacement of the storage drum by power drive 67 between the positionsshown respectively in full and broken lines in FIG. 3. This cradlestructure enables the storage drum to be carried relatively low inopening 76 of frame part 74 so that rotary axes 65 of the winch androtary axis 69 of storage drum extend in a common horizontal planedefined by tilting axis 39. This facilitates the tilting of the cradle.The successive arrangement of the two cradles enables the storage drumsto be handled readily for rapid exchange of an empty drum for a reservedrum by pivotal crane 22.

FIG. 4 shows rocking cradle 24 with contact wire storage drum 33 andguide roller 41 of winch 35, the drum and roller axes being slightlylaterally inclined because of the inclination of support and guidepulleys 18, 19. The opposite position of the pulleys and of the storagedrum and winch resulting from the zig-zag path of overhead line 4 isshown in broken lines. The rocking of the cradles about axis 39 islimited by shock-absorbing abutments 77, 78 at both sides of eachcradle. The abutments are mounted on the cradle and are arranged tocontact respective sides of bearing block 71 mounted on machine frame10.

In FIG. 5, support and guide pulleys 18, 19 are shown extending in acommon vertical plane, with their rotary axes 25, 26 extendingperpendicularly to vertical pivoting axis 27 of joint 79 connectingcarrier member 28 of the pulleys to boom 17 of lifting device 20. Holder31 for catenary support and guide pulley 18 is affixed directly tocarrier member 28 while contact wire support and guide pulley holder 31is mounted on carrier 80 for pivoting about axis 30. Carrier 80 ismounted on carrier member 28 for pivoting about horizontal axis 81extending perpendicularly to vertical pivoting axis 27 and can bepivoted by drive 32 (see FIG. 1) for changing the level of pulley 19with respect to pulley 18.

In the embodiment illustrated in FIG. 6, carrier member 84 for pulley 85supporting and guiding catenary 86 and pulley 87 supporting and guidingcontact wire 88 is mounted on laterally pivotal and verticallyadjustable crane 83 for pivoting about vertical axis 82, the diameter ofthe contact wire pulley being larger than that of the catenary pulley.Each support and guide pulley 85, 87 is rotatable about respective axis89, 90 on respective pulley holder 91, 92. Each pulley holder is mountedon carrier member 84 rotatably about axis 93 extending perpendicularlyto rotary axes 89, 90 of the pulleys. In addition, as indicated by smallarrows and phantom lines, lower pulley holder 92 may be displaceable ina direction extending parallel to pivoting axis 82 of the carrier memberso that the distance between catenary 86 and contact wire 88 may beselectively changed during installation or dismounting of the overheadline.

The embodiment of FIG. 7 has carrier member 96 for support and guidepulleys 94 and 96 for the catenary and the contact wire, cardan joint 97linking the carrier member to boom 98 of a laterally pivotal andvertically adjustable crane. Each pulley is mounted on respective holder100 and 101 for rotation about axis 99, and the pulley holders aremounted on carrier member 96 for rotation about pivoting axes 102extending perpendicularly to rotary axes 99 of the pulleys. As shown bysmall arrows, upper pulley holder 100 is vertically displaceably mountedon the carrier member and may be displaced by power drive 103 duringoperation to change the distance between the catenary and the contactwire.

The operation of machine 1 illustrated in FIGS. 1 to 5 will now bedescribed in detail, the machine being used for continuously layingoverhead line 4 comprised of two elongated flexible elements extendingabove track 7, one of the elongated flexible elements being catenarycable 3 and the other elongated flexible element being contact wire 2:

Before the installation of the overhead line is begun, the free ends ofcontact wire 2 and catenary 3 are pulled from their storage drums 33 and34 to start unreeling them, and the unreeled contact wire and catenaryare wound twice about guide rollers 41, 64 of winches 35, 36, thenpassed through tension monitoring instruments 59, 60 in contacttherewith, and led into circumferential guide grooves 72 of support andguide pulleys 19 and 18. The free contact wire and catenary ends arethen provisionally attached to a pylon 52 at the beginning of a tracksection of, for example, 1200 meter. Drives 15 and 21 of pivotal crane22 constituting lifting device 20 of the machine are then actuated toposition support and guide pulleys 18, 19 on boom 17 so that catenary 3and contact wire 2 will assume desired levels a and b between thepulleys, which have been located between the winches, and the pylon towhich the overhead line has been provisionally attached. Drive 32 isthen actuated for vertical adjustment of support and guide pulley 19 toobtain desired distance c between the catenary and the contact wire.Meanwhile, operator 51 has taken his place in operator's station 47 onwork platform 13 and the operator actuates drives 12 from control panel50 to move the work platform into the elevated position indicated inphantom lines in FIG. 1. Another operator has taken his place on workplatform 56 on tower car 55. The machine is now ready for operation.

At the start, operator 51 at central control 50 actuates drive 9 topropel the machine along the track with a pulling force of up to, forexample, 12 tons and actuates drive 45 of guiding and tensioning devices37, 38, i.e. winches 35, 36, until catenary 3 and contact wire 2, whosetension must considerably exceed that of the catenary, are sufficientlytensioned, the desired tension of the catenary being, for example, 700kg while that of the contact wire is 1000 kg. The respective tensionforces are measured by electronic monitoring instruments 59, 60 and aredisplayed to operator 51 by digital tension force indicator 49 forremote control of the drives by the operator. As soon as the desiredtension of the catenary and the contact wire has been obtained whilemachine 1 continuously advances slowly along the track in the operatingdirection indicated by arrow 14, rotary drive 66 and transversedisplacement drive 67 of storage drums 33 and 34 are actuated whilerotary drives 45 operate the winches to unreel the catenary cable andthe contact wire from the respective storage drums while the machine ispropelled along the track and the unreeled catenary cable and contactwire are subjected to a controlled tension force while being wound aboutthe winches. The tension force is controlled continuously andautomatically by tension monitoring instruments 59, 60 which so controlrotary drives 45 of the winches that the desired tension of the catenaryand contact wire are maintained constant as the machine advancescontinuously. The unreeled, tensioned catenary cable and contact wireare supported and guided by support and guide pulleys 18 and 19,respectively, and the pulleys are vertically and laterally adjusted tomaintain the tensioned catenary and contact wire at a correspondingvertical and lateral position adjacent a respective pylon 52 at one sideof the track where the overhead line is fixed in this position. Toobtain the lateral deflection of overhead line 4 along a zig-zag pathbetween succeeding pylons 52 along track 7 at opposite sides thereof,operator 51 actuates pivoting drive 16 of lifting device 20 so thatsupport and guide pulleys 18, 19 to guide and position them along thispath adjacent a succeeding pylon at the opposite track side (see FIGS. 3and 4) while maintaining the pulleys at a constant vertical adjustmentas the machine is propelled along the track whereby overhead line 4assumes the desired zig-zag path between the succeeding pylons. Thecatenary cable and the contact wire are centered along this path becausethe lateral pivoting of crane 22 by drive 16 causes support and guidepulleys 18, 19 to be rotated about their axes 29, 30 while the catenaryand the contact wire are maintained under the required tension and arefirmly guided in circumferential pulley grooves 72, and the pulleys oncarrier member 28 are automatically pivoted on boom 17 about verticalaxis 27 in the direction of the zig-zag path of the tensioned catenaryand contact wire (see the phantom line showings of pivotal crane 22 andof catenary 3 and contact wire 2 before attachment to steady brace 53 inFIG. 2).

When operator 51 has reached a steady brace 53 projecting from a pylon52 after the support and guide pulleys on the machine frame have passedthis pylon, the tensioned catenary is permanently affixed by theoperator to the steady brace. The connection of the catenary to thesteady brace may be effected while machine 1 continues to advance slowlyor while it is briefly stopped. If it is done while the machine moves,operator's station 47 is longitudinally displaced b extending thetelescoping carrier boom of work platform 13 at the same speed as themachine speed but in the opposite direction so that the operator'sstation will stand still while the operator attaches the catenary to thesteady brace. If the machine is stopped during this operation, rotarydrives 45 of winches 35, 36 and drives 66 and 67 of storage drums 33, 34are also temporarily stopped. After the catenary has been permanentlyaffixed to the pylon, machine 1 is propelled again and theabove-described operation is resumed, with all drives actuated andpivoting drive 16 of crane 22 causing the tensioned catenary and contactwire supported and guided on pulleys 18, 19 to be swung laterallytowards a succeeding pylon at the opposite side of the track. At thesame time, the operator on trailing tower car 55 affixes hangers 57between the catenary cable and the contact wire of attached overheadline 4 in a trailing operation immediately following the attachmentoperation to maintain catenary cable 3 and contact wire 2 at the desiredvertical position. Tower car 55 may advance continuously behind boom car1 while work platform 56 is longitudinally displaced along suitableguide rails in a direction opposite to the operating direction indicatedby arrow 14 so that the work platform will stand temporarily still whenthe operator attaches a hanger.

The lateral pivoting of crane 22, which causes pulleys 18, 19 to imparta zig-zag path to the tensioned catenary and contact wire supported andguided thereby, automatically tilts cradles 23, 24 as well as storagedrums 33, 34 and winches 35, 36 mounted thereon about axis 39 extendingin the direction of the longitudinal extension of machine frame 10 (seeFIGS. 3 and 4). This automatic tilting is the result of the tensileforce of the laterally moved catenary and contact wire but, if desired,this pull may be reinforced by suitable tilting drives. Any excesstilting is prevented by resilient abutments or shock absorbers 77, 78(FIG. 4) which limit the pivoting stroke of the cradles. This tilting ofthe storage drums and winches in response to the lateral movement of thesupport and guide pulleys on laterally pivoting crane 22 assures atroublefree unreeling of the catenary and contact wire and windingthereof under tension about winches 35, 36. Any slippage of the catenaryand the contact wire is dependably avoided because they are woundseveral times about guide rollers 41, 64 of the winches while they aremaintained constantly under the required tension. Lateral displacementdrives 67 laterally displace storage drums 33, 34 correspondingly to thelaterally adjacent windings so that the unreeled portions of thecatenary and contact wire always are in a vertical plane extendingperpendicularly to rotary axes 65 of the guide rollers of the winches.

This operation is repeated as the overhead line is guided in a zig-zagpath and catenary 3 is attached to the laterally inwardly projectingsteady braces 53 on succeeding pylons 52 at opposite sides of track 7,the width of the zig-zag path between the steady braces being usuallyabout 80 cm. Vertical measuring and indicating instrument 61 on liftingdevice 20 enables the level of boom 17 to be remote-controlled byoperator 51 who can actuate drive 15 so that the catenary and thecontact wire will remain constantly at desired levels a and b. Forexample, if a tunnel along the track requires a lowering of level a ofcatenary 3, the crane is correspondingly lowered while drive 32 issimultaneously actuated to raise support and guide pulley 19 (seephantom line in FIG. 1) so that contact wire 2 remains at desired levelb.

When the last pylon 52 of the track section over which overhead line 4has been installed is reached, it is affixed thereto and connected toweights in a known manner after the attachment has been loosened so thatthe required tension is permanently maintained. The installation overthe succeeding track section can then be effectuated in theabove-identified manner.

The apparatus schematically illustrated in FIG. 8 comprises two likeself-propelled machines 106, 107 of the same structure as described andillustrated in connection with FIGS. 1 to 5 for respectivelycontinuously laying and receiving overhead line 104, 105 respectivelycomprised of catenary 114, 115 and contact wire 116, 117. The overheadlines are attached to pylons 118. The machines are moved along the trackin an operating direction indicated by arrow 108 and adjacent machineframe ends are spaced from each other in this direction. The machinesare mirror-symmetrically arranged in this direction and work car 109,110 is coupled to each self-propelled machine 106, 107, each work carcomprising power-driven, vertically adjustable and longitudinallydisplaceable work platform 112, 113.

In use, leading machine 107 is operated to dismount old overhead line105 by supporting and guiding its catenary and contact wire on pulleysand reeling them under tension on storage drums in a manner proceedingreversely to the unreeling operation described hereinabove, operatingpersonnel on work platform 113 detaching catenary 115 from its steadybraces on the pylons and removing the hangers. Trailing machine 106 isoperated to install new overhead line 106 in the above-described manner,operating personnel on work platform 112 attaching catenary 114 to itssteady braces on pylons 118 and attaching the hangers.

What is claimed is:
 1. A self-propelled machine for continuously layingand immediately fixing at least one of two elongated flexible elementsof an overhead line extending above a track exclusively betweensuccessively pylons spaced alongside the track, one of the two elongatedflexible elements being a catenary cable and the other elongatedflexible element being a contact wire, which comprises(a) a machineframe having two opposite ends, (b) undercarriages supporting themachine frame at the ends thereof for mobility on the track, (c) a drivefor moving the machine frame along the track in an operating direction,(d) a driving operator's cab mounted on the machine frame, (e) apower-driven, vertically and laterally adjustable work platform mountedon the machine frame for an operator assigned to attaching the overheadline to the pylons, (f) a storage drum mounted on the machine frame, alength of the elongated flexible element being reeled on the storagedrum and the drum being rotatable at a pay-out speed for unreeling theelongated flexible element, (g) a drive control for adjusting the movingspeed of the machine frame in response to the payout speed of theelongated flexible element, (h) a lifting device mounted on the machineframe, the lifting device including (1) a power-driven, verticallyadjustable and laterally pivotal boom and(2) a power-driven support andguide pulley carried by the boom for pivoting about a substantialvertical axis and arranged to support and guide the unreeled elongatedflexible element from the storage drum to the operator on the workplatform at a constant height determined by the vertical adjustment ofthe boom and a lateral position determined by the pivoting of the boom,and (i) a device mounted on the machine frame between the storage drumand the pulley having means for continuously guiding and tensioning theelongated flexible element along a lateral zig-zag path exclusivelybetween successive pylons so that the element is automatically tensionedand, in cooperation with said lifting device, automatically centered andoriented in the longitudinal direction of the element when the elementextends in a lateral zig-zag path between successive ones of the pylonsat respective sides of the track, the guiding and tensioning deviceincluding(1) a power-driven guide roller guiding the tensioned elongatedflexible element to the support and guide pulley, and (2) a drivecontrol for the guide roller.
 2. The self-propelled machine of claim 1,wherein the support and guide pulley as well as the guide roller arearranged for guiding the elongated flexible element along a pathextending substantially perpendicularly to the rotary axes of the pulleyand roller independently of the lateral position of the boom.
 3. Theself-propelled machine of claim 2, wherein the guide roller ispositioned below the support and guide pulley and is mounted on themachine frame for tilting about an axis extending in the longitudinalextension of the machine frame and perpendicularly to the rotary axis ofthe roller.
 4. The self-propelled machine of claim 1, wherein thesupport and guide pulley as well as the guide roller havecircumferential guide grooves accommodating the elongated flexibleelement, and the pulley and roller are so positioned relative to eachother that the element will be deflected by at least 90° as it is guidedfrom the roller to the pulley.
 5. The self-propelled machine of claim 4,wherein the elongated flexible element is a relatively stiff contactwire, and the pulley and roller have substantially the same diameter ofat least about one meter.
 6. The self-propelled machine of claim 1,further comprising a carrier member for supporting the support and guidepulley rotatably about a transverse axis, the carrier member beingsupported on the boom for pivoting about a substantially vertical axiswhereby the elongated flexible element is automatically centered andoriented in a desired longitudinal direction of the element.
 7. Theself-propelled machine of claim 6, further comprising a holder mountingthe support and guide pulley on an outer end of the carrier memberremote from the vertical pivoting axis, the holder being rotatable aboutan axis extending perpendicularly to the vertical axis substantiallyparallel to the longitudinal direction of the elongated flexible elementwhereby the support and guide pulley is universally pivotal.
 8. Aself-propelled machine for continuously laying at least one of twoelongated flexible elements of an overhead line extending above a trackand attached to pylons spaced alongside the track, one of the twoelongated flexible elements being a catenary cable and the otherelongated flexible element being a contact wire, which comprises(a) amachine frame having two opposite ends, (b) undercarriages supportingthe machine frame at the ends thereof for mobility on the track, (c) adrive for moving the machine frame along the track in an operatingdirection, (d) a driving operator's cab mounted on the machine frame,(e) a power-driven, vertically and laterally adjustable work platformmounted on the machine frame for an operator assigned to attaching theoverhead line to the pylons, (f) a storage drum mounted on the machineframe, a length of the elongated flexible element being reeled on thestorage drum and the drum being rotatable at a pay-out speed forunreeling the elongated flexible element, (g) a drive control foradjusting the moving speed of the machine frame in response to thepay-out speed of the elongated flexible element, (h) a lifting devicemounted on the machine frame, the lifting device including(1) apower-driven, vertically adjustable and laterally pivotal boom and (2) asupport and guide pulley carried by the boom and arranged to support andguide the unreeled elongated flexible element from the storage drum tothe operator on the work platform at a constant height determined by thevertical adjustment of the boom and a lateral position determined by thepivoting of the boom, (i) a device mounted on the machine frame betweenthe storage drum and the pulley for continuously guiding and tensioningthe elongated flexible element, the guiding and tensioning deviceincluding(1) a power-driven guide roller guiding the tensioned elongatedflexible element to the support and guide pulley, and another guideroller connected with the power-driven guide roller for rotation intandem therewith, the guide rollers being rotatable about transverseaxes extending parallel to each other and being tiltable about an axisextending in the longitudinal extension of the machine frame andperpendicularly to the rotary axes of the rollers, the tandem guiderollers forming a winch about which the elongated flexible element maybe wound several times for obtaining a desired element tensioning rotarymoment and (2) a drive control for the guide roller, and (j) a commoncradle for the storage drum and the elongated flexible elementtensioning winch, the storage drum being mounted on the cradle fortransverse displacement parallel to the rotary axes of the guiderollers, and the cradle being mounted on the machine frame for tiltingabout the longitudinally extending axis.
 9. The self-propelled machineof claim 8, comprising two of said pulleys mounted on the boom forpivoting about a common vertical axis and two of said cradles mounted onthe machine frame in succession, each cradle carrying a respective oneof the storage drums for the catenary cable and the contact wire,respectively, and a respective one of the guiding and tensioning devicesbetween the respective storage drum and the respective pulley forcontinuously guiding and tensioning the catenary cable and the contactwire, the respective pulleys supporting and guiding the catenary cableand the contact wire unreeled from the respective storage drums to theoperator on the work platform at respective constant heightsrespectively determined by the vertical adjustment of the boom and ofthe vertical distance of the pulleys from each other as well as alateral position determined by the pivoting of the boom.
 10. Theself-propelled machine of claim 8, further comprising a common carriermember supporting the support and guide pulleys rotatably abouttransverse axes extending parallel to each other, the carrier memberbeing supported on the boom for pivoting about the common vertical axis,and a respective holder mounting each support and guide pulley on anouter end of the carrier member remote from the vertical pivoting axis,the holders being rotatable about axes extending perpendicularly to thevertical axis substantially parallel to a plane defined by the contactwire and catenary cable whereby the support and guide pulleys areuniversally pivotal and automatically centered and oriented in a desiredlongitudinal direction of the contact wire and catenary cable.
 11. Theself-propelled machine of claim 10, further comprising a power drivelinking the holder for the support and guide pulley for the contact wireto the carrier member for adjusting the vertical distance between thecontact wire support and guide pulley and the catenary cable support andguide pulley.
 12. The self-propelled machine of claim 9, wherein thecontact wire support and guide pulley trails the catenary cable supportand guide pulley in the operating direction.
 13. The self-propelledmachine of claim 9, wherein each cradle comprises a first frame partdefining an opening accommodating the respective storage drum and aadjoining frame part whereon the guiding and tensioning device ismounted, the two cradles being mounted on the machine frame insuccession in the longitudinal extension thereof.
 14. The self-propelledmachine of claim 13, further comprising reserve storage drums for thecatenary cable and the contact wire, respectively, mounted on themachine frame between the cradles.
 15. The self-propelled machine ofclaim 9, wherein the lifting device is a crane, the boom thereof being atelescopingly arranged arm extending in the direction of thelongitudinal extension of the machine frame, and further comprising apower drive linking the boom to the crane for vertically adjusting theboom and a power drive for telescopingly adjusting the boom arm, thecrane being mounted on the machine frame ahead of the cradles in theoperating direction and the power drives enabling the support and guidepulleys on the boom to be adjustably positioned above a space centeredbetween the two cradles.
 16. The self-propelled machine of claim 8,further comprising abutments at both sides of the cradle for limitingthe tilting thereof.
 17. The self-propelled machine of claim 8, furthercomprising a power drive for rotating the storage drum to unreel theelongated flexible element.
 18. The self-propelled machine of claim 8,further comprising a power drive for the transverse displacement of thestorage drum on the cradle.
 19. The self-propelled machine of claim 1,further comprising a tension monitoring instrument arranged between theguiding and tensioning device and the support and guide pulley incontact with the unreeled elongated flexible element for measurablydetermining and maintaining a selected constant tension thereof, and acentral control on the work platform, the tensioning monitoringinstrument being connected to the central control and to the drivecontrol of the guide roller.
 20. The self-propelled machine of claim 19,wherein the tension monitoring instrument has an odometer incorporatedtherein.
 21. The self-propelled machine of claim 1, wherein the drivingoperator's cab is mounted on the machine frame at a leading one of themachine frame ends in the operating direction, the lifting device ismounted on the machine frame immediately behind said cab in theoperating direction and the work platform is mounted on the machineframe at the opposite, trailing machine frame end.
 22. Theself-propelled machine of claim 18, wherein the opposite machine frameend has a material storage space adjacent the work platform.
 23. Theself-propelled machine of claim 1, wherein the lifting device comprisesa vertical measuring and indicating instrument.
 24. The self-propelledmachine of claim 1, further comprising power drives for vertically andlaterally adjusting the work platform, for vertically and laterallyadjusting the lifting device, and for longitudinally adjusting the boomto position the support and guide pulley with- respect to the guideroller, and a central control on the work platform connected to thepower drives for remote control thereof, the central control including adigital indicator instrument for indicating the tension of the unreeledelongated flexible element.
 25. The self-propelled machine of claim 1,in combination with a trailing, self-propelled tower car carrying avertically adjustable work tower for an operator assigned to detach andattach hangers connecting the contact wire to the catenary cable andsteady braces attaching the overhead line to the pylons.
 26. Anapparatus for continuously reconstructing an overhead line comprised oftwo elongated flexible elements extending above a track exclusivelybetween successive pylons spaced alongside the track, one of the twoelongated flexible elements being a catenary cable and the otherelongated flexible element being a contact wire, which comprises(a) twolike self-propelled machines for respectively continuously laying andreceiving the overhead line, each machine comprising(1) a machine framehaving two opposite ends, (2) undercarriages supporting the machineframe at the ends thereof for mobility on the track, (3) a drive formoving the machine frame along the track in an operating direction,adjacent ones of the machine frame ends of the machines being spacedfrom each other in said direction and the machine beingmirror-symmetrically arranged in said direction, (4) a drivingoperator's cab mounted on the machine frame, (5) a power-driven,vertically and laterally adjustable work platform mounted on the machineframe for an operator assigned to attaching the overhead line to thepylons, (6) a storage drum mounted on the machine frame, a length of theelongated flexible element being reeled on the storage drum and the drumbeing rotatable at a pay-out speed for unreeling the elongated flexibleelement, (7) a drive control for adjusting the moving speed of themachine frame in response to the pay-out speed of the elongated flexibleelement, (8) a lifting device mounted on the machine frame, the liftingdevice including a power-driven, vertically adjustable and laterallypivotal boom, and a power-driven support and guide pulley carried by theboom for pivoting about a substantial vertical axis and arranged tosupport and guide the unreeled elongated flexible element from thestorage drum to the operator on the work platform at a constant heightdetermined by the vertical adjustment of the boom and a lateral positiondetermined by the pivoting of the boom, and (9) a device mounted on themachine frame between the storage drum and the pulley having means forcontinuously guiding and tensioning the elongated flexible element alonga lateral zig-zag path exclusively between successive pylons so that theelement is automatically tensioned and, in cooperation with said liftingdevice, automatically centered and oriented in the longitudinaldirection of the element when the element extends in a lateral zig-zagpath between successive ones of the pylons at respective sides of thetrack, the guiding and tensioning device including a power-driven guideroller guiding the tensioned elongated flexible element to the supportand guide pulley, and a drive control for the guide roller, and (b) awork car coupled to each self-propelled machine, each work carcomprising(1) a power-driven, vertically adjustable and longitudinallydisplaceable work platform.